Split rotor construction



Oct. 15, 1929. H. v. PUTMAN 1,731,350

SPLIT ROTOR CONSTRUCTION Filed Sept. 2, 192'! 7 29 %v'- I E 4 E ,5 j 'hll 22 M/ /9 29 INVENTOR fi e/rry l orkva/z ATTOR'NEY Patented Oct. 15, 1929 UNITED STATES PATENT OFFICE ASSIGNOR TO WESTINGHOUSE CORPORATION OF PENNSYLVANIA SPLIT ROTOR CONSTRUCTION Application filed September 2, 1927. Serial No. 217,044.

My invention relates to wheels, and it has particular relation to flywheels and motor rotor members which have to be mounted on a shaft having other apparatus mounted on both ends thereof.

The principal object of my invention is to provide a novel rotor construction having a rim member which is made solid, in one piece, the inside diameter of which is sutliciently large to pass over the apparatus or obstructions at the ends of the shaft, and having a detachable hub and spider member which is split, whereby all the advantages of a split rotor construction are obtained, without the disadvantage of having to provide a rather expensive connection for the relatively heavy rim portion, with inevitable loss of strength as a result of the split. In fact, it has been practically impossible to build a large, split 'flywheel heretofore, on account of its low mechanical strength.

A further and important object of myinvention is to provide an electric motor having mechaniscal features which are especially suitable for air and ammonia and CO compressor service and similar low-speed applications.

Another object of my invention is to provide a rotor member for a dynamo-electric machine, so made that the electrical and mag netic parts of the rotor may be shipped completely assembled, and yet including a structure which is as easily assembled, in the field, as the conventional split rotor having a split electrical and magnetic rim portion.

A further object of my invention is to provide a novel construction consisting of fabricated steel members, which results in mechanical parts of greater strength, simpler and more economical construction, and smaller flywheel eifect, which is desired in some motors. Since my rotor is lighter in weight than a cast rotor, but without any sacrifice in mechanical strength, lighter shafts maybe utilized and bearing wear is decreased.

With the foregoing and other objects in view, my invention consists in the details, combinations and methods of construction hereinafter described and shown in the ac= companying drawings, wherein Figure 1 is an elevational view of a motor embodying my invention, with some of the parts broken away to show the construction,

Fig. 2 is a cross-sectional view on the line 11-11 of Fig. 1, illustrating the joint between the rim member and one of the spokes of the detachable hub member,

Fig. 3 is a similar view illustrating the posi tion of the parts when partially assembled, and

Fig. 4 is a cross-sectional view on the line IVIV of Fig. 1, showing the construction of the welded hub member.

In the drawing, my invention is shown, by way of example, as applied to a low-speed synchronous motor for compressor service, and comprising a stator member 5 which forms no part of my present invention, and a rotor member 6 which embodies a new design in accordance with my invention. The rotor member comprises a solid rim member 7 which may be made of hot rolled steel, rolled to circular form 011 a mandrel, with the ends welded together to form a continuous ring, or it may be cast steel. The rim member carries the magnetic core members and the electrical windings, which, in this case, comprise salient pole pieces 8 carrying direct-current field windings 9 and damper windings 10.

According to my invention, the rotor member 6 is provided with a split hub member 12, which is cut from a cold rolled steel slab of from 2 to 4 inches thickness. Two slabs 13 and 14 are utilized, one on each end of the hub member, thereby assuring equal bearing surface on the shaft on each end of the hub. Each of the slabs 13 and 14 is cut in half to provide two portions,'as indicated at 13 and 13 the two portions beingboltedtogether by means of four bolts 15. A plurality of rotor spokes 16 are provided, consisting of H-section steel beams which project radially from the hub member and which are welded between the hub plates or slabs 13 and 14.

The split hub and spoke member is machined after being bolted together with very fine shims temporarily placed between the two halves; a hole 18 being bored for the shaft and the ends of the spokes being machined to provide a light press fit in the rim, as indicated at 19 and 20, the press fit being about of an inch in length.

Each of the spokes 16 is provided with radially projecting tab 22 which is Welded to the spokeand extendsin overlappingrelation to the rim member 7. Bolts 23fare provided, which extend through the said tabs 22 and into the rim member for drawing uhe parts into position with a press fit, as indicated in Figs. 3' and 2'." The rim member is provided with notches 241 into Which the said tabs fit, so that the bolts are relieved from the strain of transmitting the torque or angular forces to the rim, the notches 24 being conveniently provided by Weldingu keys 25 in 1 position against :tllBiSlClBSIOli the tabsv22 afterthfe rotorhas been; bolted: together, ,the k'eys 25::being Welded.,',of-course, .to the rim-:member 1:7:

It Will readilybe :seen;; that for field: assems bly,-.the hereinabove" described construction has a distinct advantage over motors with either-a split hub', or;a'split rotor.- Therotor is. shippednompletely assembled-J To: install :the rotor on the compressor shaft, it is taken: down intouits three:- component parts, by removing the .six bolts Which holdthfe rimtothe spokes and the fourihubazbolts which: hold' the two halves rtogether: Each? aof the parts sou-is comparatively light; and 7 can :be handled easilyby ordinary/tackle ofr'the chain bloclr type Toreassembleatherotor,-the,tworhalves of the spider: are iassembled in place our the V shaft and bolted together." The-lringiis; then 35: 'srolled into position;iliftedoverthe cranksdi-sc,

(assuming the: compressonto be "of :a "duplex type), lifted into place/on the spol es-, .and drawn up has a-suifi'ciently large inside diameter ato slip over thecranlc'disconrpractically albstand-ard I I fit in said rim member, and means for holding, SetscreWs =26 are providedxin vthe; tabs 22 duplex compressorss:

whereby the rimrmaybe forced-Jolt bfthesplit hub and spider member When the rotor -is:;to.

@be taken apart.

Agdetaili d mge inthe1pr-aeti'cal embodiment of my inventionin' motor-rotors, is the provision: of press-fit portions 19 and 20:

of different diameterswvhich; may be convene: 1 -iently accomplished by-tiveldmg short" arcu ate pieces-27 to: the inner peri'phery of the rim 2' 7,-"as shown inL-F 'i'gs.= 1 .to;3,.the inneraedges of these pieces being bored to theproperrdia m-u eter forthe press =fitnl9z In. this rway,- it 'is practicalto assemble the spider amembergrby r starti ng itintoth'e rimmember from the side:

of the larger :press fit'20; aslindic'ated 'ingFiga. 3,"and,' at the sametime, to liinitthe :le'ngthof 5 the press fituportions touazasma'll ivalues' suclr. as three-quarters ofuan inch, .rthereby F fa'ci li' tating 'the assembly bymeans of [drawing mp on the bolts 23:: At the same time,=it is possible pieces 8* Without h'avingvto countersink the bolt iheads' :80 in order to 1 permit the assembly.

of the spider member With a press fit on both sides of the bolts 29.

Heretofore, a completely split rotor has been required for duplex compressor service, if the assembly Was to be made in the field. /Vhen theassemblyavas notmade in the field, it has been necessary for thecustomer to ship the compressor shaft to the factory of the electrical manufacturer for him to press his dynamo-electric machinerotoron the shaft; one of the'cranhs ofthe compressor "having first been removed to permit the assembly of a non-splitmotor rotor.

With myinvention, it is only necessary for the customer to measure his shaft diameter, and the electrical manufacturer will. then bore the split rotor'member to the exact dimension required, before-shipment:

While I have described my invention inaa preferred form as applied to dynamo-electric such as flywheels for'Water-Wheel generator-s which have forged couplings. over which the: flywheel must be assembled: It is also obvious thatmany changes may be made in ;the de-' tails of construction,Without departing from the spirit of my inventiomzl desire, therefore,., that the appended claimsshall- .be given the H broadest interpretation consistent withatheir language and the prior art;

I claimas my-invention:

1. A rotor member fora dynamo-electric... machine comprising; a solid-rim. member. having magnetic core. members: and. electricalwindings attached thereto, a split hub member, radially-extendin .supportingmembers carried by the respective-halvesof: said split hub member, the outer peripheries K of saidr radially extending; members liav 1 aspress.

said rim member in position on said radially extending members;

2. A2 rotor member for a-.dynamo-electric machine'comprising a solid rim member having. magnetic core --members and electrical. windings attached thereto, a split hub meme ber radially extending supporting members 1 carried-by the respective halves ofsaid split hub member,- the-outerperipheries :of said radially extending members havingapress fit in said rim member, and securing means com?- prising bolts fordrawing; the parts intov posi tion .With a press fit.

3. A- rotor membewfer a dynamo-electric machine comprising a solid. rim member having' magnetic core members and electricalwindings attached-thereto,- a split hub meme ber, radially extending; suppor-tinggmembers carried by the respective halves of saidsplit hub member, the outerperipheries of said I radially extending-membershaving-apress-- to utlli'ze otherubolts @291" for securin the ole" V e P fit'in said rim member, andsecuringmeans comprising a-plurality of radially projecting; tabs mtegrally'securedto said radially exe tending supporting members in overlapping relation to said rim member, and bolts extending through said tabs and into said rim member for drawing the parts into position with a press fit.

4. A rotor member for a dynamo-electric machine comprising a solid rim member hav ing magnetic core members and electrical windings attached thereto, a split hub member, radially extending supporting members carried by the respective halves of said split hub member, the outer peripheries of said radially extending members having a press fit in said rim member, and securing means comprising a plurality of radially projecting tabs integrally secured to said radially extending supporting members in overlapping relation to said rim member, and bolts extending through said tabs and into said rim member for drawing the parts into position with a press fit, said rim being provided with notches into which said tabs fit to relieve said bolts from the strain of transmitting angular forces or torque to said rim.

5. A rotor member for a dynamo-electric machine comprising a rim member having magnetic core members and electrical windings attached thereto, a hub member, radially extending supportinqm embers carr ed by sait hub member. the outer periphery of said racially extending members having a press fit in said rim member, and securing means comprising a plurality of radially projecting tabs integrally secured to said radially extending supporting members in overlapping relation to said rim member, and bolts extending through said tabs and into said rim member for drawing the parts into position with a press fit, said rim being provided with notches into which said tabs fit to relieve said bolts from the strain of transmitting angular forces to the rim.

6. A wheel comprising a solid rim member and a split hub member, radially extending supporting members carried by the respective halves of said split hub member, the outer peripheries of said radially extending members having a press fit in said rim member, and means for holding said rim member in position on said radially extending members.

7. A wheel comprising a solid rim'mei'nber and a split hub member, radially extending supporting members carried by the respective halves of said split. hub member, the outer peripheries of 'd radially extending members having a press fit in said rim menu ber, and securing means comprising bolts for drawing the parts into position with a press fi 8. A wheel comprising a solid rim member and a split hub member, radially extending supporting members carried by the respective halves of said split hub member. the outer peripheries of said radially extending members having a press tit in said rim member, and securing means comprising a plurality of radially projecting tabs integrally secured to said radially extending supporting members in overlapping relation to saidrim member, and bolts extending through said tabs and into said rim member for drawing the parts into position with a press fit.

9. A wheel comprising a solid rim member and a split hub member, radially extending supporting members carried by the respective halves of said split hub member, the outer peripheries of said radially extending members having a press fit at two spaced circles within said rim member, the radii of said circles being dilferent, and means for holding said rim member in position on said radially extending members.

In testimony whereof, I have hereunto subscribed my name this first day of September,

HENRY V. PUTMAN. 

